Solved Slider Enchantment

what is wrong ? dont working

PHP:

public function kirilmazForm($player){
        $api = $this->getServer()->getPluginManager()->getPlugin("FormAPI");
        $this->eco = EconomyAPI::getInstance();
        
      
    $form = $api->createCustomForm(function(Player $player,  array $data = null){
        $result = $data[0];
                        if($result != null){
                            $kirilmazlik = Enchantment::getEnchantment(17);
                         $kirilmazlik = new EnchantmentInstance($kirilmazlik, $result);
                         $item = $player->getPlayer()->getInventory()->getItemInHand();
                         $item->addEnchantment($kirilmazlik);
                        }

                    });

                    $form->setTitle("Büyü Menüsü");
                    $form->addSlider("Seviye" , 1, 4, 1);
                    $form->sendToPlayer($player);
      }